Engine construction and cooling method



Jan. 17, 1950 G. E. BUSKE 7 2,494,742

ENGINE cousmuc'rxon Ann coounc mimon Filed Feb. 14, 1947 s Sheets-Sheet1 X- 52 I a 54 .1

W [Avail/ K JWENToR. GILBERT E. B-USKE Jan. 17, 1950 N G. E, BUSKE2,494,742

ENGINE CONSTRUCTION AND COOLING METHOD' Filed Feb. 14, 1947 z Sheets-Shet 2 as 0 89 19 0 so '5 w s9 5: 6| 5a n .11 (an as.

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,vs 77 k V 15 89 Z 84 as 4 u a4 4 N Jan. I7 1950 s. E. BUSKE 2,494,742

ENGINE cons'mucuon m coounc names Filed Feb. 14, 1947 a Sheets-51199126no u /Enron.

QILBERTEYBUSKE Patented Jan. 17, 1950 ENGINE CONSTRUCTION AND COOLINGMETHOD Gilbert E. Buske, Anson Township, Chippewa County, Wis, asaignorto National Pressure Cooker Company, Eau Claire, Wis, a corporation ofWisconsin Application February 14, 1947, Serial No. 728,504

This invention relates to internal combustion engines such as are usedinoutboard motor units,

and has to do with the construction of such an engine and the means forand method of cooling it Outboard motors are ordinarily water cooled andthe cooling water preferably is circulated by a constant displacementtype pump, 1. e., a pump -whi ch displaces a substantially constantvolume of water per stroke, driven by the engine. It is common practiceto supply the cooling water from the pump directly to the cylinder waterjacket, or to the water jacket or cooling water space of the cylinderhead With, the water passing through the two spaces either in series orin parallel and thereafter passing around the exhaust gas passage, so asto cool the exhaust gases and aid in their condensation, reducing theirvolume. In such an arrangement, particularly when the unit is used incold water and the engine is'operated at low speed, over-cooling of theengine occurs. "That causes condensation of the water content of thecombustion gaseson the cylinder sleevw; and heads of the engine,resulting in rusting of the cylinder sleeves and piston 16 Claims. Cl.123-473) ingobjectionable cooling of the cylinder walls at low enginespeeds. Also, the cooling water space extending across the cylinder headreceives water from the cylinder water jacket in such manner that theamount of water supplied to that space varies directly as the speed ofthe engine. Consequently, when the engine is operating at the higherspeeds, with corresponding increase in heat generated, the amount ofwater supplied to the water space of the head is increased sufiicientlyto preclude overheating, without over-cooling. On the other hand, whenthe engine is operating at low speed, the supply of water to the coolingwater space of the engine head is reduced to such an extent as topreclude over-cooling, while being suflicient to prevent overheating. Inthat manner, the temperature of the engine is controlled automaticallyin accordance with its speed of operation, and effective cooling,without over-cooling,-at all speeds is assured. Further objects andadvantages of my invention will appear from the detail description.

rings and fouling of the spark plugs, which is objectionable for obviousreasons. Also, condensation of the entering fuel-air mixture'may occur,with-resultant loss in operating eiliciency of the engine, likewiseobjectionable for obvious reasons. 1 When the engine is operated athigher speeds, thesurfaces thereof in contact with the combustion gasesand the. fuel-air charge drawninto the cylinders are heated to atemperature above the dew point of such gases and objectionablecondensation may not then occur. It'will be seen that over-cooling andobjectionable condensation are apt to be encountered when the engine isoperated at low speed, as when trolling, for example.

My invention is directed to an internal combustion engine of simple andinexpensive construction and light weight, suitable for production bydie casting and particularly suited to outboard motor units, whichavoids the objections to present day engines in respect to over-coolingat low speeds, above referred to. The engine of my invention embodies anovel cooling system and method, such that adequate cooling is assuredat all speeds and over-cooling, with resultant objectionablecondensation at low speeds is prevented. More specifically, I providemeans In the drawings: V

Figure 1 is an isometric side view of an outboard motor unit embodyingthe engine of my invention;

Figure 2 is an end view of the engine of the unit of Figure 1, with thecylinder head cover plate partly broken away, certain other parts beingbroken away and the engine accessories, including the spark plugs, beingomitted for clearness of illustration;

Figure 3 is an underneath view of the'engine;

Figure 4 is a fragmentary sectional view, on an enlarged scale, takensubstantially on line 4-4 of Figure 3;

Figure 5 is a fragmentary sectional view, on an enlarged scale, takensubstantially on line 55 of Figure 3;

Figure 6 is a fragmentary transverse vertical sectional view, on anenlarged scale, of the top substantially on line of Figure 7, on anbeing broken away;

Figure 13 is a sectional view taken substantially on line |3'|3 ofFigure 2, certain parts being shown in elevation and certain other partsbeing broken away;

Figure 14 is a sectional view taken substantially on line |4-|4 ofFigure 13;

Figure 15 is a sectional view taken substantially on line ||5 of Figure13; and

Figure 16 is an isometric view of the intermediate and lower sectionsand associated parts, of the outboard unit on an enlarged scale, withcertain parts broken away and shown in section.

I have illustrated my invention, by way of example, as embodied in anoutboard motor unit utilizing a two cylinder, two cycle internalcombustion engine of the horizontal type, i. e., an engine mounted withthe cylinders thereof disposed horizontally, as is usual in outboardmotor units. It is to be understood, however, that my invention is alsoapplicable to engines having one or any suitable number of cylindersand, in its broader aspects, to vertical cylinder engines, and that theterms, horizontal, upper, lower and side, as used in this specificationand the appended claims, with reference to a horizontal engine, are usedfor convenience of description and are to be so construed and not in alimiting sense as to the substance of my invention.

The outboard motor unit 2t shown in Figure 1 comprises an underwatersection 2|, an intermediate section 22, and an upper section comprisinga motor support tube 23 having a flanged fitting 24 fixed to its lowerend. The sections 2| and 22 are secured together and to fitting 24 in asuitable manner, convenientlyv by bolting, as is known; A hearing sleeve25, formed of two sections bolted together, fits about the support tube23, between a mounting plate 26 fixed on the upper end of the tube 23and the fitting 24, there being a washer 21 between the lowerend ofsleeve 25 and the upper end of fitting 24. An arm 28,

rigid with the upper end of sleeve 25, carries a clamp bracket 29suitably mounted thereon, by means of which the unit may be secured tothe stern sill or transom of a boat. When the unit is mounted on a boat,the sleeve 25 supports tube 23 and the parts carried thereby for turningmovement about the axis of the tube.

The mounting plate 26 is of dished formation, open at its top, where itis provided with an outwardly extending peripheral flange 30, and is ofsubstantial depth interiorly opening directly into the upper end ofmotor support tube 23. Flange 30 is of generally elliptical shape inplan'and has its upper surface machined to provide a seating surface 3|of generally elliptical shape, as is shown more clearly in Figure 14. Atits under face, mounting plate 26 is provided with down wardly openingrecesses (Figure 13) carrying elements 32 cooperating with elements 33carried by 'a flange 34 at the upper end of sleeve 25. The

elements 32 and 33 are included in steering stabilizing means for holdintube 23 in desired adjustment about its axis. The stabilizing meansreferred to is not included in my instant invention and need not befurther described here.

The lower section 2 l of unit 20 is provided with the usual skeg 35(Figure 1) extending downward therefrom. This section 2| houses thegearing and associated parts for driving the propeller shaft, mountedtherein, from a drive shaft 35 (Figure 13) extending from the power headdownward through motor support tube 23 and the intermediate section 22.The propeller shaft (not shown) is rotatably mounted in section 2|,projects outwardly therebeyond, and has suitably mounted thereon apropeller 31. Section 2| also carries a constant volume water pump 33,

of suitable known type, having an underwater intake 39 opening throughone side of section 2|.

A discharge passage 4|) leads from the discharge of pump 38 and opensinto the lower end-of a bore 4| extending through the upper end ofsection 2|. A water supply tube 42, preferably formed of aluminum, fitssnugly at its lower end in bore 4|] and extends upward therefrom throughintermediate section 22 and support tube 23, alongside the drive shaft35. The upper end of tube 42 communicates with the water'spaces of theengine of the power head for supplying cooling water thereto, as willappear more fully presently. I The intermediate. section 22 of unit 20flares downward and is provided, at the stern thereof, with anunderwater discharge opening 43 of substantial size, adjacentanti-cavitation plates 44 at the lower endand opposite sides of section22.

The mounting plate 25 carries the power head, including the engine andits accessories. Since my instant invention has to do particularly withthe engine, so far as the power head is concerned, in the accompanyingdrawings, I have omitted the engine accessories as well as certain partsof the engine itself not necessary to a disclosure of my invention, forclearness of illustration. The engine 45 is shown as a two cycle twocylinder engine, with its cylinders disposed horizontally. It comprisesa substantially cubiform cylinder block 46 having at one end avertically disposed crank case section 41 (Figure 12) integraltherewith, and provided with two superposed horizontal cylinders 48,with cast in liners or sleeves 49 of cast iron, extending outward fromits other end. The outer ends of the cylinders 43 are closed by acylinder head 50 comprising an outer end wall structure 5| providing twoconnected cupped head members 52 (Figure 13) seating on the outer endsof cylinders 45 in sealing engagement therewith, with an interveningsealing gasket 53. The head 50 is provided with a peripheral wall orflange 54 connected to the end wall structure 5| by a web element 55(Figure 2) having, adjacent flange 54, top and bottom slot-like openingsor ports 55 and 51, respectively.

The fiange'54 (Figures 12 and 13) extends out-- ward a short distancebeyond the end wall structure 5| and receives, at its outer end, a fiatcover plate 58 seating thereon with an intervening sealing gasket 59.The plate 55 is shaped conformably to the cylinder head I. (Figure 2)which. in outer end view, approximates a figure-8 shape, and is providedwith spaced outwardly extending bolting ears 5. disposed for alignmentwith spaced bolting bosses 5| integral with flange 54. Each head 52 isprovided with an off center outwardly extending boss 62, the outer endof which is in the plane of the outer end of flange 54. The boss 52 issuitably bored and tapped to receive the reduced neck of a spark plug 53passing through plate 58 and screwing into boss 52, between which andthe inner face of plate 53 there is interposed a sealing gasket 64disposed about the neck of the spark plug. A sealing gasket 05 is alsoprovided about the neck of each spark plug 83, between the body thereofand the outer face of the cylinder head cover plate 58. I thuseffectively guard against possible leakage, either interiorly orexteriorly of the cylinder head, about the spark plugs, and the lattermay also function as supplementary means for securing the plate 58 inposition should looseness develop in the main securing means, to bereferred to presently. The cover plate 58 is spaced, by flange 54,outward a short distance from the end wall structure (Figures 12 and 13)and defines therewith and with flange 54 a cooling water space 66extending across the cylinder head members 52.

The outer end of the body portion of cylinder block 46 extends outwardbeyond the cylinders 48 radially thereof and is machined off to providea seating surface. Flange 54 extends from the end wall structure 5|inward along the cylinders 48 for a considerable distance, such that itseats on the seating surface of the outer end of the body portion of thecylinder block 48, with an intervening sealing gasket 61. Through bolts88, having heads 59 at their Outer ends, pass through ears 68 of coverplate 58 and the tubular bosses 5| of flange 54, and screw into theouter end of the body of cylinder block 45, appropriately bored andtapped for that purpose. Spring washers 18 are interposed between coverplate 58 and the heads 69 of certain of the bolts 58, certain others ofwhich may pass also through a flange H of a shield 12, disposed at theouter face of plate 58 and extending about the upper one of the sparkplugs 63. It will be seen that the bolts 58 secure cylinder head 58 inposition seated on cylinder block 45 in sealing engagement therewith,and secure the cover plate 58 tightly seated on the outer end of thecylinder head flange 54, these bolts 88 constituting the main securingmeans, previously referred to, for the cylinder head assembly. When thecylinder head 58 is secured in position on the cylinder block 48, flange54 is spaced outward from cylinders 48 radially thereof definingtherewith a cooling water space or jacket 13 extending about thecylinders and opening freely into head space 66 -through the upper slotor port 58 in web element 55, as will be explained more fully later.

The cylinder block is provided, in one side thereof, with a recess 14(Figures '1 and 12) of generally oblong shape in side View, extending tosome extent about the cylinders 48 and, at its inner end. about thecrank case section 41. A thickened wall 15 frames the outer opening ofrecess 14 and projects a short distance outward beyond the body portionof cylinder block 46. Wall 15, like recess 14, has its longer axisdisposed vertically and is of channel cross section at its top and itsends. A cross web 16, at the midlength of the top element of wall 15,separates the latter interiorly into an outer channel 11 and an innerchannel 18 (Figure 10) adjacent crank case section 41. A suitable numberof openings 19 (Figures 6 and 7)one or more-are bored in the cylinderblock 45, from the upper end of outer channel 11, adjacent across web18, into a water inlet passage 80 (Figures 6 and 13) formed in cylinderblock 48 at the top thereof. The passage 88 flares toward, and opensthrough, the outer end'of the body portion of cylinder block 48 into thecylinder water jacket 13, at the top thereof, as shown in Figure 13. Thepassage 88 and openings 19 .8 I establish free communication between thecylinder water jacket 18 and the outer channel 11 of wall 15, as will beclear from what has been said.

The outer face of wall 15 is fiat and is machined to provide a seatingsurface. A cover structure 8I (Figures 7, 8, 9, and 12) is suitablysecured, conveniently by screws 82, to wall 15 and seats thereon, withan intervening gasket 88 providing a water tight seal therebe'tween. Thecover structure 8| comprises an inner flat closure plate 84 and an outercover plate 85 of dished formation seating on plate 84. with anintervening gasket 88 providing a water tight seal therebetween. Thescrews 82 pass through appropriately disposed bosses of plate 85 andthrough plate 84, and thread into bosses of wall 15, as will readily beunderstood. The plates 84 and 85 define between them a water space 81.Plate 84 is provided, adjacent its bottom, at its outer end, with anopening 88 which overlies the lower end portion of channel 11 of wall15, and, adjacent its top, with an opening 88a which overlies the topportion oi channel 11, gasket 83 also being provided with openings inregister with openings 88 and 88a, respectively. Plate 84 is alsoprovided, at its top, with an opening 89 overlying and opening into thetop portion of channel 18 of wall 15, through an opening in gasket 83 inregister with opening 89. The cover plate 85 is appropriately formedinteriorly, as will be clear from Figures 8 and 11, to provide freecommunication between water space 81 and channels 11 and 18, throughopenings 88 and 88a and opening 89 of closure plate 84. It will beclear, from what has been said, that water space 81 of cover structure8| opens into channel 11 at the bottom and the top thereof and intochannel 18 at the top thereof.

The crank case section 41 is provided, at its upper end, with asemi-cylindrical boss 98 (Figures 2, 7, and 13) and, at its lower end,with a second'semi-cylindrical boss 9i. An outer crank case section 92is bolted to crank case section 41 and is provided, at its upper andlower ends with semi-cylindrical bosses 93 and 94, respectively. Thebosses 93 and 94 are complementary to bosses 98 and 9I and definetherewith collars receiving bearing bushings 95 and 96 in which a 0vertical crank shaft 91 is rotatably mounted. An

oil seal 98, of known type, is disposed about crank shaft 91, at theupper end of bushing 95. A center main bearing ring I88 is suitablymounted in the crank case, centrally thereof, and fits snugly in acorresponding groove in the crank shaft 91, with the shoulder at theupper side of the groove seating on ring I88, which carries the load ofthe crank shaft. The ring I88 and its mounting separate the crank caseinteriorly into two separate chambers or compartments I8I into which thecylinders 48 respectively open, at their inner ends. The seal providedby the ring I88 and the cooperating shoulder of the crank case 91 is ofimportance. Since crank case compression is utilized to charge thecombustion spaces of the cylinders 48, one compartment I8I of thecylinder is under pressure while the other compartment is under partialvacuum. Under such conditions, objectionable leakage between the twocompartments will occur unless carefully guarded against. The sealprovided by the shoulder of crank shaft 91 seating on the upper face ofbearing ring I88 effectively prevents any objectionable leakage betweenthe crank case compartments I81.

The outer crank case section 92 is provided, at its outer side, with anappropriately disposed and formed pad I02 (Figures 3 and 12) havingtherein passages I03 respectively opening into the compartments IOI.Each of the passages is controlled by an outwardly opening and inwardlyclosing poppet valve I04. An intake passage and spring housing memberI05 is bolted to pad I02, at the outer face thereof, with an interveninggasket I06. Member I05 is provided with pockets I01, which receivecompression springs I08 urging the valves I04 closed, and with a neckI09 having an intake passage IIO opening into the spring pockets I01,which overlie and open directly into the respective valve pockets III ofpad I02. The outer end of neck I09 is adapted to bolting thereto a stackof a carburetor (not shown). The valves I04 are actuated in openingdirection by cam followers I I2 pivotally mounted in the crank case andoperated by appropriately disposed cams II3 on the cam shaft 91. Theprovision of means for admitting the combustible fuel mixture directlyto the crank case compartment, or compartments, has an important bearingon the disposition of the exhaust gas recess 14, as will appear morefully presently. Within the broader aspects of my present invention, anysuitable means may be provided for admitting the combustible fuelmixture directly into the crank case.

The cylinder -block 46 has formed therein, at the opposite side thereoffrom recess 14, two transfer passages IE4 (Figure 12) flaring toward andrespectively opening at one end into the crank case compartments IOI.Passages II4 open at their other ends into hollow rectangular bosses II5formed integral with block 46. The outer faces of bosses II5 are flatand formed to provide seating surfaces on which closure plates II6 seat,with intervening gaskets H1. The plates II6 are secured to bosses II'Iin a suitable manner, conveniently by screws H8, and effectively closethe outer sides thereof. Inlet ports I I9 are bored through the walls ofthe respective cylinders 48, to which ready access is had through thebosses I I5, these ports II9 opening directly into'the transfer passagesII4, as will be clear. Also, exhaust ports I20 are bored through thewalls of cylinders 48, at the opposite side thereof from inlet ports H9and somewhat nearer the outer ends of the cylinders than inlet ports H9.The recess 14 in the cylinder block 46 gives ready access to thecylinders 48 for boring the exhaust ports I20 therein, as will be clear.Pistons I21 operate in cylinders 48 and have operating connection, bymeans of connecting rods" I22, to'the crank shaft 91. Each piston isprovided, at its outer or head end, with an appropriately formedextension I23 for deflecting the entering fuel-air mixture charge towardthe outer end of the cylinder and causing displacement therefrom of theburned gases to and through the exhaust outlet.

The provision of means for admitting the combustible fuel-air mixturecharge directly to the crank case compartments renders it possible tohave the water inlet passage 80 at the top of cylinder block 46, withthe transfer passages H4 and the recess 14 at opposite sides thereof.The recess 14 may thus be disposed to best advantage, with the exhaustports I20 opening directly into its outer end. Further, the recess 14may have an outlet opening 524 of ample size, directly through thebottom of cylinder block 46 and its associated crank case section 41,disposed within the area enclosed by a seating surface I25 (Figure 3),formed on the bottom of cylinder block 46 and crank case section 41,conforming to the seating surface of the rearward or stem portion offlange 30 of mounting plate 26. The cylinder block 46 is also provided,at the bottom thereof and within seating surface I25, with a downwardlyopening hollow rectangular boss I26 (F 8- ures 3, 14 and 15) from whicha water outlet passage I21, extending outward along the under side orbottom\ of block 46, opens through the outer end of block 46 at thebottom of the cylinder water jacket 13. The bottom of boss I26 providesa seating surface I28 flush with and supplementary to seating surfaceI25, and the bottom of crank case section 92 is provided with a seatingsurface I29 constituting a continuation of seating surface I25 andconforming to the seating surface of the forward portion of flange 30 ofmounting plate 26. The engine block and crank case assembly is thusprovided, at the bottom thereof, with a seating surface, comprising thesurfaces I25 and I29, conforming to, and adapted to seat accuratelyupon, the upper face of flange 30.

The lower cylinder 48 is provided, adjacent its bottom or under side,with two exterior lengthwise ribs 48a (Figures 2, 4, and 13), disposedat opposite sides of the bottom port 51 of head 5I. The ribs 48a extendfrom web element 55 of head 5| to the outer end of cylinder block 46,defining between them a water outlet passage or channel 121a leadingfrom port 51 to the outer end of passage I21. Ribs 48a also extendradially outward from sleeve 48 to within a short distance of skirt orflange 54 of cylinder head 5|, defining therewith slot-like openingsI21b providing restricted communication between the cylinder waterjacket 13 and channel I21a.

The bearing sleeve at the bottom of the crank case, comprising thebosses 9I and 94, is provided with a downwardly opening annular channelI26. A plate I3I seats on the bottom of the bosses 5| and 94, with anintervening gasket I32, to which it is suitably secured, conveniently byscrews I33 threading into suitably disposed bosses, and closes thebottom of channel I30. The plate I3I is provided with a roundedextension I34 (Figure 14) underlying a rounded projection 9Ia of boss3|, and with a depending cylindrical neck I35. A tube I36 is secured, atits upper end, in neck I35 and extends therefrom downward. When theengine is mounted on plate 26, tube I36 extends downward about driveshaft 36, the upper end of which is splined to the lower end of crankshaft 91 (Figure 13), into the upper portion of motor support tube 23,in concentric spaced relation thereto and to shaft 36. A recess I31 isformed in an extension 15a of wall 15 (Figure 3) and opens into thelower end of channel 16 and into the annular channel I30, establishingcommunication therebetween. The outer side of recess I21 is closed byextension 92a of crank case section 92.

The mounting plate 26 is provided, at the after or stern portion thereofwith an upwardly opening hollow boss I38 (Figures 13, 14, and 15)substantially rectangular in plan, the top of which is flush with theupper face of flange 30 and provides a seating surface I38asupplementary thereto. The forward or inner end wall I39 of boss 138 isprovided with a water outlet aperture I46 of substantial size openinginto mounting plate 26.

.As will be clear from Figures 3, 13, 14, and 15,

seating surfaces I25, I26 and I26, at the bottom will be clear,

9 of the cylinder block and crank case assembly, provide a continuousseating surface area which conforms to the seating surface area offlange 38 of mounting plate 26 and the top of boss I38. The cylinderblock and crank case assembly. is suitably bored and tapped, in the areaof the seating surfaces I25 and I29 thereof, for reception of headedscrews I44 passing through flange 38 of plate 26, there being springlock washers I45 interposed between the heads of screws I44 and theunderface of flange 38. The engine may thus be mounted upon the mountingplate 26 with expedition and facility, with a sealing gasket I46disposed between the seating surfaces thereof. Gasket I46 may beprovided with an extension conforming to the opposed seating surfaces ofthe bosses I26 and I38, disposed therebetween.

The projection 9Ia of boss 8| a stepped bore 8Ib, of larger diameter atits lower end portion, extending from its under face and opening intochannel I38. A backing washer I (Figure 13), which may be formed ofbrass or other suitable metal, seats in the lower portion of bore 8Ib,and a sealing washer I42 also seats in the lower portion of bore 8|b andis confined between washer MI and extension I34 of plate Ill. Theextension I34 of platei|3| is provided with an aperture which registerswith the lower end of bore 8Ib. The upper end portion of water tube 42is straight lengthwise and is offset outward a shortdistance from thebody portion thereof, to which it is connected by a short curve or bend,as shown. The sealing washer I42 preferably is formed of a syntheticrubber, such as "neoprene," and is of an inner diameter to flt tightlyabout tube 42 in sealing contact therewith. In mounting the engine onthe mounting plate 26, the straight upper end portion of tube 42 isinserted through the washers I42 and I, the inner diameter of washer Ibeing slightly greater than the outer diameter of tube 42, as will beunderstood. To assist in inserting tube 42 through the washers I42 andI, the upper end of tube 42 is cut on a slant, as shown. It from whathas been said, that when the engine is mounted on plate 26 and is inoperation, water will be delivered from the discharge of pump 38 throughtube 42, under pressure to channel I38. By removing the screws I theengine and the parts carried thereby, constituting therewith the powerhead, may be lifted as a unit from the mounting plate 26. The watersupply tube 42 may then readily be withdrawn through the motor supporttube 23, for inspection, cleaning, repair or replacement.

The wall and the cover structure 8| mounted thereon define, with recess14 of cylinder block 46, an expansion chamber, of adequate volume, forthe exhaust gases discharged from the cylinders 48 directly into thatchamber through the exhaust ports I28. When the engine is mounted onplate 26, the exhaust expansion chamber opens directly into that plate,through opening I24, as will be clear, and tube I36 extends downwardabout drive shaft 36 into the upper portion of motor support tube 23, inconcentric spaced relation to both thereof.

is provided with substantial extent by heat .before passing to thecylinder water jacket, which ward about the In the operation of theengine, when the unit is in use, the pump 38 delivers water underappropriate pressure to the water supply tube 42. The water isdischarged from tube 42 into channel I30 (Figures 3 and 13), where iteifectively cools the lower crank shaft bearing so as to preventoverheating thereof. From channel I30 the water flows through recess In(Figure 3) into channel 10 18 and upward through the latter channel andopening 88 of closure plate 84 (Figure 7) into water space 81 (Figures10 and 11) of the exhaust expansion chamber cover structure 8|. It willbe noted that the cover structure is of a height equal to that of thecylinder block 46 and of a length approximating thatof cylinder block 46(Figures 7 and 13), being of substantial extent in a plane parallelingthe cylinder axes, while the water space 81 of cover structure 8|(Figure 12) is of but slight thickness or extent perpendicular to thatplane. Accordingly, the water entering space 81 is spread out therein ina thin layer or sheet of considerable extent, and is there subjected tothe heat of the hot exhaust gases discharged into chamber 14. the coverstructure 8| is thus heated to a substantial extent by the exhaust gasesand quickly cools and condenses such gases, substantially reducing thevolume thereof and precluding objectionable back pressure in the engine.The water flowing through channel 18 will also be heated by the exhaustgases and will assist in cooling and condensing them. The water leavesspace 81 at the top thereof, through opening 88a (Figures 7. 9 and 10)in closure plate 84,-and adjacent the bottom thereof, through opening 88in closure plate 84. The openings 88, 88a and 882.11 open into the waterspace 81' of the cover structure 8|.

It will be noted that the opening 88 is at least as large as opening 89(Figure 9), and opening 88a is substantially smaller than opening 88,providing a restricted outlet. The water entering channel 11 throughopening 88 will flow upward through channel 11 under substantialpressure and velocity and will mix, in the top of channel 11, with waterdischarged thereinto through opening 88a from space 81. The waterflowing through channel 11 will also be heated by the exhaust gases andwill assist in condensing them. From what has been said, it will be seenthat the entering cold water is utilized to best advantage for coolingand condensing the exhaust gases, and is also heated to a derived fromsuch gases is conducive to avoidance of over-cooling of the engine,particularly when it is operating at low speed.

The water discharged under pressure into channel 11, as above, flowsthrough openings 18 into passage 88 (Figure 13) and thence into thecylinder water jacket 13. The water flows downcylinders 48, within thcylinder Jacket 13, and escapes through the restricted openings I21binto the channel I21a, from which it flows into passage I21 and thence,by way of bosses I26 and I38 and mounting plate 26, into tube 23.

Since, as noted, the pump 38 is a constant volume pump and delivers afixed volume of water per stroke, the amount of water delivered by thepump to the engine cooling system varies directly as the speed of thepump, that is, as the speed of the engine. When the engine is operatingat low speed, as when trolling for example, the rate of supply of waterto the cylinder water jacket 13 may be insufllcient to maintain itcompletely filled. In such case the water flows downward about thecylinders and escapes through the restricted openings I21b. But little,if any, water then enters the head space 66 through port 56, and space66 may then be substantially empty, such water as may enter that spaceflowing downward therethrough by gravity across the cylinder heads andescaping through port 51. The engine The cold water flowing through willthen be adequately cooled while being heated sufliciently to precludeobjectionable condensation and assure smooth and efficient operation ofthe engine. As the speed of the engine increases, the rate of supply ofwater to the cylinder water jacket 13 increases and water may then flowcontinuously through port 56 into the head space 66 completely fillingit, after which the cooling water flows under pressure in two parallelstreams downward through the jacket 13 and the space 66. At high speedoperation of the engine, the water flows through jacket 13 and space 65at increased velocity. Since the amount of heat generated in the engineincreases with the speed thereof, the increase in flow of cooling waterwith increase in engine speed, assures adequate cooling withoutover-cooling, which assures smooth and eflicient high speed operation ofthe engine while avoiding objectionable condensation therein of thecombustion gases. Likewise, and to the same end, cooling of the engineis adjusted automatically to intermediate speeds thereof.

It will be seen that, by the cooling system of my invention, the extentof cooling of the engine is automatically varied in accordance withengine speed and is such that, at any given engine speed, the engine isadequately cooled, while over-cooling is avoided and smooth and emcientoperation without objectionable condensation in the engine of combustiongases is assured. The velocity of flow of cooling water through thechannels of wall 15 and through the cover structure at, of the exhaustexpansion chamber 14, increases as the engine speed increases. At highspeed operation of the engine, there is practically no risk ofovercooling, and the problem then becomes one of adequate cooling, whichis fully provided for by the cooling system of my invention. At lowspeed operation of the engine, the water flows through the channels ofwall I and through cover structure 8|, of the exhaust expansion chamber14, at low velocity. The water is then preheated to a greater extentthan at high engine speeds, which is desirable. In that connection, atlow engine speed the heat generated by the engine is much less than athigh engine speed, and the problem then becomes principally one ofpreventing overcooling of the engine with the attendant objectionspreviously referred to. The increased preheating of the water at lowengine speed is desirable as being conducive to avoidance ofover-cooling, and the decreased cooling of the exhaust gases is stilladequate due to the decreased volume of such gases at low engine speed.The water flowing into mounting plat 26 and thence downward about tubeI36 further cools and condenses the exhaust gases while tending toproduce a partial vacuum or suction effect in the expansion chamber,which contributes to prevention of objectionable back pressure in theexhaust passages of the engine and to increased efliciency thereof. Theexhaust gases discharged into mounting plate 26 mix with the waterflowing down the motor support tube 23. The mixture of water and exhaustgases flows from tube 23 into intermediate section 22 of unit 20 and isdischarged therefrom under water, through opening d3, as will be clearfrom what has been said.

The crank case section 41 flares generally away from the cylinder block46, the transfer passages H4 are straight lengthwise and open into andflare toward crank case section 41, and water passages 80 and I21 arestraight lengthwise and flare toward and open through the outer end ofcylinder block 46. Likewise, all other passages and recesses in thecylinder block, except the drilled passages or openings, areappropriately formed and disposed to provide draw for die casting, andall seating surfaces on the cylinder block 46 and appurtenant parts areflat and, in general, perpendicular to other seating surfaces, tofacilitate machining thereof. The cylinder block and crank case unit ofthe engine is thus well suited to production by die casting, and suchmachining of surfaces thereof as may be required can be performedquickly and easily. Likewise, the cylinder head 50 is well suited fordie casting, as is the crank case section 92, and the cover plate 85. Itwill be seen that the engine of my instant invention is so designed andconstructed that the stationary parts thereof may readily be produced bydie casting, or by stamping, require but little machining, which may beperformed with expedition and facility, and may be quickly and easilyassembled, rendering it possible to produce an engine of exceptionallyhigh efficiency at comparatively low cost.

It will be understood that changes in detail may be resorted to, withoutdeparting from the field and scope of my invention, and I intend toinclude all such variations, as fall within the scope of the appendedclaims, in this application in which the preferred form only of myinvention is disclosed.

I claim:

1. In an outboard motor unit, an internal combustion engine comprising asubstantially horizontal cylinder having a water jacket provided with awater inlet and with a restricted water outlet adjacent its lower side,a head for said cylinder having a cooling water space extending downwardacross the outer end of said cylinder, said water space opening into thecylinder water jacket adjacent the upper side of the latter and beingotherwise substantially closed thereto and having a water outletadjacent its lower side substantially separate from the cylinder waterjacket, the latter with its inlet and outlet providing a first path offlow for cooling water, said head cooling water space providing with itsinlet and outlet a second path of flow for cooling water substantiallyseparate from said first path of flow, and means for supplying coolingwater to said cylinder water jacket comprising a pump driven at variablespeed corresponding to the speed of said engine.

2. In an outboard motor unit, an internal combustion engine comprising asubstantially horizontal cylinder having a water jacket provided with awater inlet adjacent its upper side and with a restricted water outletadjacent its lower side, a head for said cylinder having a cooling waterspace extending downward across the outer end of said cylinder, saidwater space having adjacent its upper side a water inlet port openinginto the cylinder water jacket and being otherwise substantially closedthereto, said water space being provided adjacent its lower side with awater outlet port substantially separate from the cylinder water jacketand communicating with the water outlet of said cylinder jacket, saidcylinder water jacket with its inlet and outlet providing a first pathof flow for cooling water and said head water space providing with itsinlet and outlet ports a second path of flow for cooling watersubstantially separate from said first path of flow, and means forsupplying cooling water to the water inlet of said cylinder water jacketcomprising a water pump driven by said engine.

3. In an engine for an outboard motor unit,

' a horizontal stricted water outlet adjacent its'lower side, and

- a head for said cylinder having'a cooling water space extendingdownward across the outer end of said cylinder, d water space openinginto the cylinder water et adjacent the upper side of the latter andbeing otherwise substantially closed thereto and having a water outletadjacent its lower side substantially separate from the cylinder waterjacket; the latter with its inlet and outlet providing a first path offlow for cooling water; said head cooling water space providing with itsinlet and outlet a second path of flowfor cooling water substantiallyseparate from said first path of flow.

.top of the latter-and being sent its bottom, said cylinder having awater jacket provided with a water inlet and with a re-.

7. In" an outboard motor unit, an internal combustion engine comprisinga substantially horizontal water jacketed cylinder having a restrictedwater outlet adjacent its bottomand a head for said cylinder having acoolingwater space extending downward across'th'e outer end of saidcylinder, said space opening adjacent its top into the cylinder-waterjacket adjacent the otherwise substantially closed thereto. and having awater outlet adj ajacketed exhaust chamber with the water jacketadjacent the top thereof 4. In an outboard motor unit, an internalcombustion engine comprising a substantially horizontal cylinderhaving awater jacket provided water inlet adjacent its upper side ,and

restrictedwater outlet adjacent its lower head for said cylinder havinga cool thereof opening into said'cylinder water jacket and being"provided at its under side with. a crank shaft bearing openingsurrounded by a cooling water channel opening' into the exhaust chamberwater jacket, and

means for supplying cooling water to said channel and thence through theexhaust chamber water jacket to said cylinder water jacket comprising awater pump driven by-said engine.

- 8, In an outboard motor unit, an internal combustion engine comprisinga substantially hori zontal water jacketed cylinder having a restrictedwater outlet adjacent itsbottom and a head for said cylinder ha acooling water space extending downward across the outer end of saidcylinder, said space opening adjacent its top into and said head waterspace providing with its inlet and outlet ports a second path or flowfor cooling water substantially separate from said 5. In an outboardmotor unit, an internal combustion engine comprising a water jacketedcylinder disposed with its axis substantially horizontal in the normaluse of said engine, the water jacket of said cylinder having arestricted water outlet adjacent its lower side, and a head for saidcylinder having a cooling-water space extending downward across theouter end of said cylinder,

said space opening adjacent its upper side intothe cylinder water jacketand being otherwise substantially closed thereto and having a wateroutlet adjacent its lower side, means for supplying cooling water tosaid cylinder water jacket comprising a water pump driven by saidengine, and means for subjecting the cooling water to heat derived fromthe hot exhaust gases of said engine in its flow to said cylinder waterjacket thereby condensing the exhaust gases and preheating the waterprior to its entering said cylinder water jacket.

its lower side, said engine having a water jacketed exhaust chamber withthe water jacket thereof opening into said cylinder waterjacket adjacentthe upper side thereof, and means for supplying cooling water to theexhaust chamber water jacket and thence to said cylinder water jacketcomprising a water pump driven by said engine.

the cylinder-water jacket adjacent the top of the latter; and beingotherwise substantially closed thereto and having a water outletadjacent its bottom, said engine having at one side thereof a waterjacketed exhaust chamber with the water jacket thereof opening at itstop into said cylinder water jacket and being provided at its under side7 with a crank shaft bearing opening surrounded 'by a cooling waterchannel opening into the exhaust chamber water jacket adjacent thebottom thereof, and means for supplying cooling water to said channeland thence through the exhaust chamber water jacket to said cylinderwater jacket comprising a water pump driven by said engine.

' 9. In an outboard motor unit, an internal combustion engine comprisinga substantially horizontal water jacketed cylinder having a wateroutletadjacent the bottom of its water jacket,

said engine having an exhaust chamber with a hollow cover structuredefining a cooling water space of considerable extent in one plane andof comparatively slight extent perpendicular to said plane, said enginehaving passages openingfrom the water space of said cover structure intosaid cylinder water jacket adjacent the top thereof, and means forsupplying cooling water to said water space of said cover structurecomprising a. water pump driven by said engine.

1 10. In an outboard motor unit, an internal combustion enginecomprising a substantially horizontal water jacketed cylinder having awater outlet adjacent the bottom of its water jacket, said engine havingat one side thereof a downwardly opening exhaust chamber defined :inpart by a wall of channel formation projecting outward from said engine,a hollow cover structure seating on said wall defining a cooling waterspace of considerable extent in a plane substantially parallel with thecylinder axis and of comparatively slight extent perpendicular to saidplane, said wall being separated interiorly into two channels eachextending in part across the top of said chamber, one of said channels:opening at its top into said water space and the other of said channelsopening at its bottom and at its top into said water space, said enginehaving engine having a water 1 passages opening from thetop of saidother channel into the water jacket of said cylinder adjacent the topthereof, and means for supplying coolin water to said one channel" andthence through said water space and other channel and passages to saidcylinder water jacket comprising" a water pump driven by said engine.

. the inner face of said flange defining therewith 11. In an outboardmotor unit, an internal combustion engine comprising a substantiallyhorizontal water jacketed cylinder having a water outlet adjacent thebottom of its water jacket, said engine having at one side thereof a:downwardly opening exhaust chamber defined in part by a wall of channelformation projecting outward from said engine, a hollow cover structureseating on said wall defining a cooling water topo! said chamber, one ofsaid channels opening at its top into said water space and the other ofsaid channels opening-:"at'its bottom and at its top into said waterspace, saidengine having passages opening from the top of said otherchannel into the water j'acketof said cylinder adjacent the top thereofand being provided at its under side with a crank shaft bearing openingsurrounded by a cooling water channel opening into said one channeladjacent the lower end thereof, and means for supplying cooling water tosaid channel surrounding said bearing opening and thence through saidone channel and said space and other channel and passages to saidcylinder water jacket comprising a water pump driven by said engine.

12. In an outboard motor unit, an internal combustion enginecomprisingacylinder block having a crank case at one end and a substantiallyhorizontal cylinder sleeve projecting outward beyond its other end, anda cylinder head secured to said block closing the outer end of saidsleeve having an inwardly extending flange seating on the outer end ofsaid block extending about said sleeve in spaced relation theretodefining therewith a waterjacket, said block having a water inletpassage opening through its outer end into said water jacket adjacentthe top thereof and a water outlet passage opening through its havingtwo exterior lengthwise ribs disposed at opposite sides of said outletpassage extending radially outward of said sleeve into proximity torestricted water escape openings from said water I jacket to the spacebetween said ribs, said head defining a cooling water space extendingacross the outer end of said cylinder having a port at its top, openinginto said water jacket and a port at its bottom opening into the spacebetween said ribs, said cooling water space being otherwise closed tosaid cylinder water jacket.

14. The method of cooling an internal combustion engine having a waterjacketed cylinder and cylinder head, which comprises supplying water tothe cylinder water jacket by a water pump of substantially constantvolume per stroke driven by said engine while restrictedly dischargingwater from the cylinder water jacket independently of discharge of waterfrom the cylinder head water jacket, and supplying to the water jacketofthe cylinder head water overflowing thereinto from the cylinder jacketand discharging water from the cylinder head water jacket independentlyof discharge of water from the cylin-- der water jacket.

15. The method of cooling an internal combustion engine having asubstantially horizontal water jacketed cylinder and a cooling waterspace extending downward across the cylinder head,

bustion engine having a substantially horizontal beyond its other end,and a cylinder head secured to said block closing the outer end of saidsleeve having an inwardly extending flange seating on the outer end ofsaid block extending about said sleeve in spaced relation theretodefining therewith a water jacket, said block having a water inletpassage opening through its outer end'into said water jacket adjacentthe top thereof and a water outlet passage opening through its outer andadjacent the bottom of said sleeve, the latter REFERENCES CITED Thefollowing references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 743,556 Perkins Nov. 10, 19031,375,110 Rowledge Apr. 19, 1921 1,434,348 Bull Oct, 31, 1922 1,457,944Short June 5, 1923 1,500,668 Church July 8, 1924 1,754,689 MacPhersonApr. 15, 1930 2,063,825 Otwell Dec. 8, 1936 2,227,247 Conover Dec. 31,1940 GILBERT EQBUSKE.

